Cherie Blair joined hundreds of schoolchildren for the opening of the first stage of the new £214m Royal Opera House in London.

The prime minister's wife appeared on stage alongside Sir Anthony Dowell, director of the Royal Ballet, to introduce the first performance to be staged in the newly refurbished building in Covent Garden.

At an event overshadowed by news that she is expecting her fourth child, Mrs Blair received rapturous applause from the audience as she spoke of the pregnancy.

"Every baby is a miracle and this one was certainly a surprise.

I am looking forward to going through this pregnancy very much."

She added that it was important that all children were given the opportunity to experience the arts, saying: "The future of our country and the future of the arts depends on our children."

The revamped Royal Opera House promises greater public access

Mrs Blair then watched an hour-long performance by members of the Royal Ballet including Prima ballerina Darcey Bussell and children from the Royal Ballet School.

Cherie Blair's visit marks the start of a three-week opening festival of events before the official opening of the Royal Opera House on 1 December.

Prima ballerina Darcey Bussell and tenor Placido Domingo will top the bill at the opening night event, which will be attended by the Queen.

As part of its commitment to provide greater access, the new "user friendly" Opera House will also be putting on special public performances.

The 450-seat Linbury Studio theatre will house free lunchtime concerts and performances for schools, students and the local community.